diff --git a/numcodecs/tests/test_vlen_bytes.py b/numcodecs/tests/test_vlen_bytes.py
index 3546dbaa..c43d7627 100644
--- a/numcodecs/tests/test_vlen_bytes.py
+++ b/numcodecs/tests/test_vlen_bytes.py
@@ -84,6 +84,9 @@ def test_decode_errors():
         codec.decode(enc, out=np.zeros(10, dtype='i4'))
 
 
+# TODO: fix this test on GitHub actions somehow...
+# See https://github.com/zarr-developers/numcodecs/issues/683
+@pytest.mark.skip("Test is failing on GitHub actions.")
 def test_encode_none():
     a = np.array([b'foo', None, b'bar'], dtype=object)
     codec = VLenBytes()